“In a small room at the U.S. Air Force Academy stands a scale model of a town, complete with power and other utilities, looking as if someone had upgraded their model railroad with radar towers and air defense equipment. The pieces are connected to tiny Raspberry Pi controllers running Modbus, a protocol commonly used in the gear that controls real-world utilities. Last week, Defense Secretary Ash Carter showed up to watch a group of cadets reverse-hack a tiny radar tower until they could turn it on and off at will.”
Source: The Tiny Town Where Air Force Cadets Learn to Drop ‘Cyber Bombs’ – Defense One